<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        /* 
            九九乘法表双重for循环
            *
            **
            ***
            ****

            i     num（j的最大值）
            0      1
            1      2  
            2      3

            i+1=num;
        */
        for (let i = 1; i < 10; i++) {

            let star = '';
            for (let k = 1; k < i + 1; k++) {
                star = star + (k + "*" + i + "=" + i * k) + "";
                

               
            }
         
            console.log(star)
        }



      // 代码是调试出来,不是写持来
    </script>
</body>

</html>